A simulated microgravity influenced essentially the metabolism of storage polysaccharides of the potato minitubers. An increase of synthesis and accumulation of starch and an enhancement of phosphorylase activity were observed in the minitubers during a long-term clinorotation. At the same time the mono- and disaccha-rides content decreased, which pointed to the intensification of their utilization for starch synthesis. The correlation between the enhancement of enzyme activity and the increase of starch content is revealed.